Corn plants are typically planted in rows spaced a predetermined distance apart. Harvesting units of corn headers are spaced a corresponding distance apart so as to be capable of following the rows while inducting the corn plants. When entering and moving through a stand of corn, the harvesting units of the header are typically preceded by row dividers that separate the adjacent rows of plants for harvesting by the respective harvesting units. The harvesting units are configured and operable for receiving the stalks of the corn plants of the respective rows in succession, and removing the full or intact ears of corn, for conveying by other apparatus from the header to processing apparatus within the harvesting machine. Typically, the harvesting units can comprise a variety of devices operable for harvesting the corn ears from the stalks, including deck plates defining a stalk receiving channel, gathering chains having teeth operable for carrying the corn ears rearward to a conveying apparatus of the header and snapping rolls located in association with the deck plates for pulling the corn stalks downwardly. In a typical configuration, the gathering chains are located above the deck plates and the snapping rolls are located below. The snapping rolls are rotatable for pulling the corn stalk downwardly, through rearward moving fingers of the gathering chains, to bring the ears to bear against the top edges of the deck plates so as to be detached from the stalks thereby. The detached ears are then carried toward the rear of the header by the gathering chains for conveying by other apparatus into the harvesting machine, while the collapsed stalks are left on the field.
In a typical harvesting unit, the deck plates can be spaced a variety of distances apart. For instance, the spacing can be large such that a gap or space exists between the adjacent edge of the deck plate and the side of the stalks, on one or both sides of the stalks. Or, the spacing can be smaller, such that edges of the deck plates contact the sides and even pinch or squeeze the stalks. In the first instance, if the gap or space is large, an advantage is that more of the remaining plant residue or trash, e.g., leaves, stalks, husks, can fall through the enlarged channel so as not to build up in the harvesting unit, and not be conveyed into the harvester. But, a disadvantage is that corn ears may get stuck more easily between the deck plates. As a result, these ears may form an obstruction or trash build up for a next stalk entering the harvesting unit. Further, when such a corn ear remains stuck, a substantial amount of kernels will become detached until the ear is reduced in size and falls through the gap. As such, when the gap is set too large, considerable losses may occur. In the second instance, if the pinch force is too great, stalks may get caught between the deck plates and bunch up in the channel and be damaged or broken such that, again, ears are lost, and more trash may be retained and carried by the gathering chains into the header.
As proposed solutions to the problems set forth above, it is known for the deck plates to be movable laterally, e.g., using an actuator such as a hydraulic cylinder, to allow adjusting the width of the stalk receiving channel, from the operator cab based on observations and/or operator preferences, mainly, based on estimates of stalk diameter, and/or to achieve good stalk flow into the harvesting units. However, if the operator lacks experience, or is inattentive, the channel width can be too big or small, resulting in the above listed problems. It is also known for the deck plates to be spring mounted to bring the edges of the deck plates to bear against the largest diameter stalks currently located therein while exerting a pinching force. This provides a degree of automatic adjustment and can eliminate gaps or spaces between the edges of the deck plates and the stalks. However, this force will be strictly a function of the spring constant and the degree of compression or extension thereof, if working properly. As another problem, sugars from the stalks and dust adhered thereby to the plates and surrounding structure so as to reduce and even overcome the spring forces and inhibit free lateral adjusting movements of the plates, such that they can stick open too widely or too narrowly so as to undesirably affect the pinching force, disrupt stalk flow and ear removal, and the like.
It is therefore an object of the present invention to provide in an improved manner of controlling deck plate positioning of a corn header, thereby at least partly overcoming one or more of the shortcomings and problems mentioned above.